Modern consumer electronics, such as game consoles, notebook computers, smart phones, personal digital assistants, and location based services devices, as well as enterprise class electronics, such as servers, storage arrays, and routers, are packing more integrated circuits into an ever shrinking physical space with expectations for decreasing cost. Contemporary electronics expose integrated circuits to more demanding and sometimes new environmental conditions, such as cold, heat, and humidity requiring the overall system to provide robust thermal management solutions. Higher performance, more functions, lower power usage, and longer usage of battery power are yet other expectations placed upon contemporary electronics.
As more functions are packed into integrated circuits and more integrated circuits into a package, more heat is generated degrading the performance, the reliability, and the lifetime of the integrated circuits as well as the overall system. Numerous technologies have been developed to meet these new requirements. Some of the research and development strategies focus on the system power supplies, ventilation, and enclosure fans while others focus on the integrated circuit technologies and associated integrated circuit packaging. Other focus on other forms of thermal management solutions, such as heat sinks/slug, heat spreaders, or localized fans directly over the integrated circuit. Yet other solutions may use a combination of solutions.
More specifically, enclosure fans are often used to evacuate warm air from enclosures in which electronic systems are contained. For example, most computer systems include one or more cooling enclosure fans to aid circulating air inside the enclosures and for maintaining the temperature inside the enclosures within an acceptable range. The increased airflow provided by the enclosure fans typically aids in eliminating heat that may otherwise build up and adversely affect system operation. Employing enclosure fans is especially helpful in ensuring proper operation for certain integrated circuits, such as central processing units (CPUs), with relatively high operating temperatures.
Control of fans in a system typically involves a fan control unit executing a fan control algorithm. A fan control algorithm may determine the method for controlling one or more fans that are configured to evacuate warm air from the electronic system. These requirements and functions also apply to localized fans over an integrated circuit.
Fan speed is usually determined by system software looking at the processor status. This needs a lot of effort to optimize (and debug) the operational efficiency of the fan. The processor may utilize a signal conveying to the system its status (busy or idle). If only one bit is used for this signal, only two statuses may be indicated, resulting in problems.
For example, when a processor is busy, such as when performing numerous and lengthy floating point calculations, the fan needs to run fast in order to cool down the processor. Conversely, when the processor is idle, the fan may run at a lower speed or revolution per minute (RPM) or may even be turned off consuming less power and/or increasing the battery life usage of the electronic system.
With current technology, the fan speed is fixed at one or two modes depending on processor's status (idle or busy). Although the processor may consume and throw off different amounts of power/heat depending on how busy it is (e.g. 40W, 60W, or higher), the fan in the busy mode will turn at one speed and use a constant amount of power. This may result in the system using extra power unnecessarily.
Sometimes processor operation will cause more heat than the fan can handle. The inability to remove excessive heat from electronic systems may lead to permanent damage of the system as well as the integrated circuits. The economic impacts may be best illustrated in the following example. As a product goes through various life cycle phases, such as design, design testing, manufacturing pilot runs, production test, and final production, the cost increases by an order of magnitude from one phase to the next phase of the life cycle when a change is required to a major electronic component of the electronic system.
Designing cooling solutions for systems is also a time-consuming process for the thermal design engineer. Typically, a controller card is required to be designed and built for controlling the fan speed and other functionality, such as failure detection and alarm settings. Often times, the design and construction of multiple control cards are required so as to test them in real world applications to obtain the right combination of fans, fan speeds, alarm settings, etc. Multiple iterations of installing sample fans in a system, determining the adequate fan speeds and power required, and testing the fans in the system, for example, are costly and inefficient.
Thus, a need still remains for an electronic system with a dynamic thermal management solution providing lower power consumption, longer battery life operation, lower cost manufacturing, improved yield, and higher reliability for the electronic systems. In view of the ever-increasing need to save costs and improve efficiencies, it is more and more critical that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.